JPS581086A - Metallic plating method of carbon fiber bundle or cloth - Google Patents

Abstract

PURPOSE:To uniform thickness of plating, and to improve adhesiveness owing to improvement of wetness, by baking a carbon fiber bundle or its cloth consisting of carbon single fibers on which a bundling agent is applied, in an oxidation atmosphere, before plating. CONSTITUTION:A carbon formed substance, especially, a carbon fiber bundle or its cloth consisting of single fibers on which a suitable bundling agent is applied in advance is subjected to a burning treatment in the air or an oxidation atmosphere. As a result, a bundling degree or a coupling degree of the carbon single fibers is raised, therefore, the applied bundling agent or coupling agent is decomposed, and subsequently, when the carbon fiber itself is oxidized, roughing and activation of the surface of the single fibers are caused. As a result, equalization of metallic plating and a rapid improvement of adhesiveness can be attained. In this regard, the baking treatment conditions are very important, and especially, excessive baking exerts influence on a characteristic of the carbon fiber itself, mechanical strength of the fiber bundle or cloth is remarkably dropped, and both plating work and post-treatment work are remarkably deteriorated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of metal plating carbon formations, particularly carbon fiber bundles or cloth, by electroless or electroplating.

Until now, when metal plating was applied to fiber bundles made of a large number of single carbon fibers or woven fiber cloth, the plating solution could not penetrate into the slits between each single fiber, and the center of the fiber bundle The carbon fibers near the cross-joint parts of the fiber cloth were hardly plated, and the wettability of the metal plating to each carbon fiber was poor, resulting in insufficient adhesion and the metal plating peeling off easily. .

In addition, in order to uniformize the plating on carbon fiber bundles or cloth, a method of increasing the agitation during plating and immersing the carbon fiber bundle or cloth in an aqueous solution of solvent and surfactant was used to improve wettability. However, all of them were just imperfect metal plating.

Accordingly, an object of the present invention is to provide a method for providing a metal plating having a uniform thickness and good adhesion on a carbon fiber bundle or cloth as described above.

In the method according to the present invention, when applying metal plating to a carbon formation, in particular a carbon fiber bundle or cloth consisting of a single fiber coated with a suitable sizing agent in advance, the carbon fiber or cloth is placed in air or an oxidizing atmosphere in advance. Perform a firing process, thereby
This is a plating method that achieves uniform thickness of metal plating and improved adhesion by improving the plating resistance by making carbon ruts tighter during metal plating or by making it easier to unravel the carbon single fibers that make up the cloth.

More specifically, according to the present invention, a sizing agent or a bonding agent is applied to increase the degree of convergence or bonding of carbon single fibers by firing in air or an oxidizing atmosphere, that is, in the presence of oxygen. is decomposed and then the carbon fibers themselves are oxidized to cause roughening and activation of the surface of the single fibers, thereby achieving uniformity of metal plating and dramatic improvement in adhesion.

Therefore, the firing processing conditions are very important, especially excessive firing will affect the properties of the carbon fiber itself, greatly reducing the mechanical strength of the fiber bundle or cloth, and the subsequent plating and post-processing. The workability of processing will be extremely deteriorated.

The firing conditions are determined by the relationship between the firing temperature and time, but based on various conditions, 200C is the lower limit temperature, and if it is less than 200tZ', sufficient uniformity and adhesion of metal plating cannot be obtained. The firing time also ranges from about 20 minutes to 200 minutes.

Practical methods for this firing treatment include leaving the material in a firing furnace for a predetermined period of time or passing it through a tube furnace at a predetermined speed. Any method to obtain it can be applied.

Next, the effects of the method according to the present invention will be explained by the following examples. ” Example 1 A fiber bundle consisting of 600 single carbon fibers with an average diameter of 10 μm was heated using Hitachi Chemical H8101B stock solution 6% and hydrochloric acid 32%.
%, in a catalyst aqueous solution having a liquid composition of 62% water at room temperature.
After soaking for a minute, it was thoroughly washed with water. Next, after processing under the firing treatment conditions shown in Table 1, copper sulfate pentahydrate 1o9
/l, sodium ethylenediaminetetraacetate 309/l,
Polmari (30%) 10 ml/l, hydroxide) l
) A plating layer was formed by immersing the plated layer in an electroless copper plating solution having a liquid composition of 509/l and a liquid temperature of 50 r, followed by sufficient water washing and drying. For the carbon fiber bundle thus prepared, the uniformity of plating on the carbon fibers was determined using a cross-sectional microscope, and the adhesion and mechanical strength were determined using a bending test method. The judgment results are also shown in Table 1.

Table 1 ○---Good △---Slightly inferior ×-11 Inferior As a result, the processing conditions that satisfy all three of the uniformity of plating thickness, adhesion, and mechanical strength are from condition i to condition t. Particularly good results are obtained under conditions 0, q, and r. Among these, FIG. 1 shows a cross section of a fiber bundle that was particularly fired under the treatment conditions (q, r) of a treatment temperature of 350 C and a treatment time of 60 to 90 minutes. As shown,
A copper plating layer 2 of about 6 μm is uniformly formed around the carbon fibers 10 in the center, and has good adhesion, and there is no substantial decrease in mechanical strength compared to a similar carbon fiber bundle that has not been subjected to any treatment. It wasn't there.

Example 2 A carbon fiber bundle consisting of 3000 single carbon fibers with an average diameter of 10 μm was treated in air at a temperature of 350 C and a treatment time of 60
In an electric steel plating bath having a bath composition of 55 g/l of cuprous cyanide, 67 g/l of sodium cyanide, 10 F//l of hydroxide,
Copper plating was performed for 6 minutes with sufficient stirring under the plating conditions of bath temperature 50C and cathode current density 4A/drn'', followed by sufficient water washing and drying to prepare a sample, and the same as in Example 1. When the uniformity of the metal plate thickness, adhesion, and mechanical strength were evaluated, all six specimens showed good properties.

As described above (according to the present invention), by performing plating after firing at a predetermined temperature and time as a pretreatment, plating that has a uniform thickness and good adhesion can be achieved on each carbon single fiber. It is possible to provide a layer of carbon fiber, and it is not subjected to any sintering treatment (・It can maintain mechanical strength equivalent to that of carbon fiber.

Up to now, carbon fiber bundles made of carbon single fibers have been used as samples, but compared to when plating carbon fiber cloth, this has the same effect as the outer periphery near the center of the bundle. This was chosen because it is difficult to provide good plating, and it is obvious that carbon fiber cloth can be plated with good quality by the same method.

Furthermore, as is clear from the above explanation, the method according to the present invention can be similarly applied to other formed objects such as single fibers, particles, chips, etc., as long as the material of the member to be plated is carbon. Furthermore, copper was used as the plating type in the above experiments, but in electroless plating, nickel-phosphorus, cobalt-phosphorous, etc. were used, while in electroplating, silver, nickel, gold, tin, etc. It will be easily understood that plating with metals of

[Brief explanation of drawings]

FIG. 1 is a diagram showing a cross section near the center of a carbon fiber bundle plated by the method according to the present invention, observed under a microscope. 1-m-carbon fiber 2-11 steel plating layer fi

Claims (1)

[Claims] 1. A method for metal plating a carbon fiber bundle or cloth, which comprises firing a fiber bundle or cloth made of carbon single fibers coated with an appropriate sizing agent in an oxidizing atmosphere, and then applying metal plating to the fiber bundle or cloth. . 2. The method of metal plating a carbon fiber bundle or cloth according to claim 1, wherein the firing treatment is performed at a temperature of 200C or higher. 3. The method of metal plating a carbon fiber bundle or cloth according to claim 2, wherein the firing treatment is performed for 20 minutes to 200 minutes. 4. The metal plating method for a carbon fiber bundle or cloth according to any one of claims 1 to 6, wherein the metal plating is performed by an electroplating method. 5. The metal plating method for a carbon fiber bundle or cloth according to any of claims 1 to 3, wherein the metal plating is performed by an electroless plating method.